Primary Tumor: Adjuvant Therapy and Recurrence Surveillance

5-FU versus capecitabine as adjuvant therapy for rectal cancer

Commentator: DANIEL HALLER, MD

Comment:

I generally use infusional 5-FU rather than capecitabine as adjuvant therapy for rectal cancer. No prospective data demonstrate that we can substitute with capecitabine in this setting, although it is implied that we can based on rough equivalency data in advanced disease. However, in the adjuvant setting, solid data exist for infusional 5-FU.

Nor do I use CAPOX rather than FOLFOX. I am waiting for data from the AVANT trial — evaluating the addition of bevacizumab to either adjuvant FOLFOX4 or CAPOX in Stage II and III colon cancer — to tell us whether they are equivalent. Though they appear roughly equivalent or noninferior for capecitabine/oxaliplatin in advanced disease, even a small decrement in activity in the adjuvant setting might mean a difference in cure rate. Thus, I tend to be much more rigid in my approach in the adjuvant setting, and less so in the metastatic setting where I have multiple chances to treat for palliation. We usually have only one chance to cure the patient.

On the other hand, if a patient had an infected port and refused to go back on infusional 5-FU, I’d probably administer capecitabine, based on the NSABP dose and schedule, rather than bolus 5-FU.

Selection of adjuvant therapy for patients with Stage II colon cancer

Commentator: DANIEL HALLER, MD

Comment:

In patients with Stage II disease, if they have high-risk factors, such as poorly differentiated tumors, perforation, obstruction, lymphovascular invasion, inadequate nodal sampling and their prognoses is as bad as those with Stage III, then FOLFOX may be considered. However, I believe the option also exists for the patients at very good risk to not receive adjuvant therapy or an intermediate choice of 5-FU.

We know that in patients who are unselected, 5-FU does offer approximately a four-percent survival benefit. That brings the bar up so high that the incremental gain from oxaliplatin was not visible in the MOSAIC trial. This year, survival data from the MOSAIC and PETACC-3 trials will be released, and we will be publishing them together.

Surveillance of patients with Stage II or III colon cancer after primary treatment

Commentator: DANIEL HALLER, MD

Comment:

After primary therapy, we follow patients with Stage III, T3/N2 colon cancer every three months with a CEA and every six months with CT scans of the abdomen and pelvis. We typically do that for five years. By that time, at least 85 to 90 percent of all recurrences will have occurred, so continuing the same schedule after that point becomes less productive. If hepatic metastases develop and we are considering resection, we first perform a colonoscopy — if the patient has not had one in the past year — to rule out a new primary colon tumor, which is pretty common in patients who’ve had prior colon cancer.

My general rule of thumb is if someone has a Stage II tumor with such a good prognosis that I don’t even consider chemotherapy, that I also don’t perform a surveillance except for colonoscopy. In other words, if I believe they will not relapse, then I shouldn’t be looking for relapse.